The immune system functions to protect the body against harmful antigens, bacteria, viruses, toxins, blood or tissues from another person or species, and cancer cells. Immune system disorders can lead to hyperactivity or hypoactivity of the immune system. In cases of immune system hyperactivity, the body attacks and damages its own tissues. In cases of immune system hypoactivity, also known as immune deficiency, the body's ability to fight foreign antigens is diminished, which often leads to a greater vulnerability to infections.
The enzyme arginase metabolizes L-arginine to L-ornithine and urea. Besides its fundamental role in the hepatic urea cycle, arginase is expressed in some cells of the immune system of some mammals. However, it is unclear if interferences with L-arginine metabolism can be used to treat immune conditions. Importantly, several challenges exist in formulating exogenous Arginases as a therapeutic agent that is suitable for clinical administration.